Black Tank Valve Won't Fully Close

[jrkahut]

Hi All,

A few weeks ago I was dumping my tanks on my 2011 Flying Cloud 27FB and when I went to go close the black tank valve it wouldn't go in all the way. I naturally thought something might have been stuck in there so I pulled it back out and ran fresh water through the sewer flush system hoping it would wash it away. Needless to say that did not work. Afterwards, I also noticed the bar itself is slightly lower than the hole. See pics:

The T bar is fully engaged into the tank here. Notice the difference in color on the pipe. That is where the difference is in where the valve used to close and where it now closes.



I have tried the following:

- Filling up black tank near 100% and letting it flush very quickly
- Using the Camco Dual Flush Pro Valve System to flush the tank the opposite way (back into the tank)

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

The only thing I can figure is there is either
1. Something stuck in the groove where the valve slides in to seal the tank or
2. the valve is going underneath the tank and it is slowly leaking that way. Just a little black water is leaking into the hookup receptacle when I take off the cover. I would say less than a cup.

I had to loosen the bolt at the end of the T-handle to fit it back into the 2 wire slots to make it secure.

Any thoughts on this? Ideally I would like to be able to flush whatever is in there out and not have to take it in for service. Normally I would work on this myself, but with a black tank I'm going to leave it to the experts if repairs need to be made.

Thanks in advance for all your insight!

[Jenfm]

Hello, sorry it doesn't look like you got any responses. We're having the exact same problem and we're quite certain nothing went down the toilet that could be jamming it. Any further advice would be appreciated. On our 2020 International the valve seems pretty inaccessible. Thanks.

[BayouBiker]

In the case of the original post, it appears from the second photo that the handle extension slipped partially outward and has shifted from parallel. My 2018 international has a different extension arrangement where the bar is continuous back to the valve.

The original post indicated the valve was only slightly leaking meaning it was very nearly fully closed. Probably the bend prevented getting enough force to fully seat the valve blade.

You have not indicated if yours is leaking and if so how much?

[Jenfm]

Thanks, no ours is not leaking, it's just that we can't get the handle to go back in all the way so we can bring the retaining hooks over the handle ends. It used to fit fine. Does anyone know - is there some kind of a seal or o-ring in there that could have rolled and would keep the gate from going all the way in to the seat? Thank you.

[BayouBiker]

There is indeed a round seal assembly, but if its not leaking, then it is seated. So either the pipe/tank system has shifted a bit or the valve handle extension has shifted. I'll go take a closer look at mine and see if there is an easy way to resolve this.

[AirMiles]

I've got the same problem on my 2018 GT27. The black tank lever used to operate easily, completely close and have no leaks. Now it won't close all the way, I need to slam it closed at the very end and it leaks a 1/4 cup or so each time I pull the outside cap off.

On my 2017 FC25FB I also had the same thing happen. It worked from new for a while. Then started acting just like described above. Then one day I saw a rivet shaft sitting in the pipe after emptying the tank and then it started working perfectly again. I think there is a rivet shaft stuck in the black tank seal.

[BayouBiker]

So I looked at the parts manual and the 25 has by far the longest distance from the valve to the handles so this is the trailer where this issue is going to surface. My handles shift around seems like each time I use them. Sometimes they fit just right, sometimes they are hard to get the retainers latched. I didn't ask previously if you have already tried loosening the handle length adjustment nut behind the handle and screwed the handle all the way in to shorten the length?

[Rocinante]

Regarding the valve that's not leaking but doesn't close enough to fit under the clips: Check and see whether you can simply adjust the length of the valve handle by screwing or unscrewing it on the stem. There may be a locknut that helps prevent accidentally doing this. This may be all you need do to get it fitting properly under the clips again. However, do consider this an early warning regarding the valve itself. Just like a marine toilet, if you didn't eat or drink it first, it doesn't belong in the toilet. Yes, that includes TP.

Regarding the valve that's actually doing a slow leak: There's a very good chance you've gotten some TP or other non-digestible material stuck into the valve housing and it's just now starting to be a problem. We had the same issue with our 27FB. It finally got drippy enough, despite all efforts to flush it out, that we had to take it in for service where they said the only fix was to replace the valve. Several hundred dollars later (because our black tank valve is deep inside the belly pan and extra labor was involved), we got her all fixed up and came to the conclusion reached above, which would have saved us all that money if we had honored that idea earlier. To whit: if you didn't eat or drink it first, it does *not* belong in the toilet.

Yeah, having a little tightly covered TP Bucket in the bathroom isn't particularly pleasant, but it's more pleasant than paying another significant sum of money to replace the valve again.

Lastly, regarding our admonition above: you don't have to agree, and that's OK with us. Your money, your Airstream, put whatever you want into the black tank if that's how you want to "roll."

Good luck to both of you!

[Mollysdad]

Originally Posted by Jenfm

We're having the exact same problem and we're quite certain nothing went down the toilet that could be jamming it. On our 2020 International the valve seems pretty inaccessible. Thanks.

You're certain YOU didn't put anything to jam it, but Airstream might have.
Mine had a leak and I found a tip off a tube of calk in the exit. Lucky for me it flushed (no pun intended) out and solved the problem.

BTW, to the OP, if you only get a cup of liquid, it's not a leak, if it leaked, the drain would fill from the point where the gate valve is to the cap, much more than a cup.

Here's a band aid temporary fix. Adding a gate valve past your cap.
I considered this but my leak stopped on it's own.

[SeeMore]

If you ever raised a baby I bet you changed a diaper. Working on your tank valve is not that nasty. Wear gloves and your COVID-19 mask and you are good to go.

SO… the valve ia a simple blade in a sleeve that has two circular rubber gaskets surrounding the opening and rub against the blade (see photos). When the blade will not return to the fully closed position it is usually one of two reasons: blockage in the track or a slipped gasket. Once a gasket moves and gets disfigured, your solution is to rebuild the valve assembly with new gaskets. If the issue is something in the track, physically removing material causing the blockage is the fix.

These pics will help you imagine what you will encounter if you drop the pan for access.

[Jenfm]

Thanks for all the info, we did try adjusting the nut, can't be adjusted enough to move the handle sufficiently. Good point about the fact there could have been something in the tank from the factory, never thought of that, we've only had it out a few times. We're going to try to put a camera up it in the next few days and see if we can see an object or rolled gasket (we've flushed it really well!). And I really appreciate the parts pictures so we know what we're looking for. Thanks.

[Jenfm]

Well, Mollysdad (and others) you were certainly correct, we didn't put anything down the tank, but Airstream sure did! When we inserted our camera we could clearly see a foreign object interfering with the seat, I could post some pics from the in-tank footage, but it's kind of abstract. So we fashioned a hook and lo and behold pulled out this giant piece of sharp metal. I appears when the factory was cutting the hole in the tank they let the metal cutting fall in the tank and didn't bother to remove it. You can see in the last pic (taken with the Snap-on camera inside the tank) it did chew up the disk a little and crease the seat gasket. It still seats fine, but I'm documenting it with the factory and the dealer should we have any problems in the future! Thanks again for your help.